Nanosecond Electric Pulses: A Novel Stimulus for Triggering Ca2+ Influx into Chromaffin Cells Via Voltage-Gated Ca2+ Channels
| Autor: | Indira Chatterjee, Sophie Choe, P. Thomas Vernier, Gale L. Craviso, Paroma Chatterjee |
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| Rok vydání: | 2010 |
| Předmět: |
Time Factors
Chromaffin Cells Analytical chemistry Membrane Potentials Cellular and Molecular Neuroscience chemistry.chemical_compound Electricity Animals Repolarization Calcium Signaling Membrane potential Voltage-gated ion channel Voltage-dependent calcium channel Chemistry Sodium channel Sodium Cardiac action potential Cell Biology General Medicine Hyperpolarization (biology) Calcium Channel Blockers Biophysics Tetrodotoxin Calcium Cattle Calcium Channels Extracellular Space Ion Channel Gating |
| Zdroj: | Cellular and Molecular Neurobiology. 30:1259-1265 |
| ISSN: | 1573-6830 0272-4340 |
| DOI: | 10.1007/s10571-010-9573-1 |
| Popis: | Exposing bovine chromaffin cells to a single 5 ns, high-voltage (5 MV/m) electric pulse stimulates Ca(2+) entry into the cells via L-type voltage-gated Ca(2+) channels (VGCC), resulting in the release of catecholamine. In this study, fluorescence imaging was used to monitor nanosecond pulse-induced effects on intracellular Ca(2+) level ([Ca(2+)](i)) to investigate the contribution of other types of VGCCs expressed in these cells in mediating Ca(2+) entry. ω-Conotoxin GVIA and ω-agatoxin IVA, antagonists of N-type and P/Q-type VGCCs, respectively, reduced the magnitude of the rise in [Ca(2+)](i) elicited by a 5 ns pulse. ω-conotoxin MVIIC, which blocks N- and P/Q-type VGCCs, had a similar effect. Blocking L-, N-, and P\Q-type channels simultaneously with a cocktail of VGCC inhibitors abolished the pulse-induced [Ca(2+)](i) response of the cells, suggesting Ca(2+) influx occurs only via VGCCs. Lowering extracellular K(+) concentration from 5 to 2 mM or pulsing cells in Na(+)-free medium suppressed the pulse-induced rise in [Ca(2+)](i) in the majority of cells. Thus, both membrane potential and Na(+) entry appear to play a role in the mechanism by which nanoelectropulses evoke Ca(2+) influx. However, activation of voltage-gated Na(+) channels (VGSC) is not involved since tetrodotoxin (TTX) failed to block the pulse-induced rise in [Ca(2+)](i). These findings demonstrate that a single electric pulse of only 5 ns duration serves as a novel stimulus to open multiple types of VGCCs in chromaffin cells in a manner involving Na(+) transport across the plasma membrane. Whether Na(+) transport occurs via non-selective cation channels and/or through lipid nanopores remains to be determined. |
| Databáze: | OpenAIRE |
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